Review of Microfracture for Knee Osteoarthritis

Knee joint replacement is not the only way to treat joint degeneration and pain from osteoarthritis. Other surgical options are now available. In this review article, the basic science, pros and cons, and use of microfracture are presented.

Microfracture refers to a surgical technique that involves making tiny holes through the joint cartilage and subchondral bone. Subchondral refers to the layer of bone underneath the cartilage.

The puncture goes all the way through to the bone marrow. A small amount of bleeding occurs as bone marrow seeps into the hole. Holes are drilled around an area of cartilage defect. Then holes are spaced carefully through the defect. Too many holes too close together can result in less than ideal healing of the cartilage.

Success of the microfracture technique depends on the rehab program afterwards. Healing requires an environment that ensures the marrow clot will mature into repair tissue and fill in the defect. The authors present two specific rehab programs.

The first rehab protocol is for lesions on the femoral condyle or tibial plateau. The femoral condyle is the round end of the femur (thigh bone) that attaches to the tibia (lower leg bone). The tibial plateau is the flat part at the top of the tibia. The femoral condyle rests on the tibial plateau to form the knee joint.

The second rehab program is for lesions of the patellofemoral joint. This is where the patella (knee cap) moves up and down over the femur during knee motion. Each rehab program is broken down into several phases.

During the first phase, joint motion is restored while protecting the marrow clot. Continuous passive motion (CPM) is maintained with a special machine. Patients are only allowed to touch the foot to the floor for the first eight weeks. They cannot put any weight on that foot.

The program progresses through a strengthening phase then endurance phase. These two phases are followed up with a performance phase. This final phase is for those patients who are athletes trying to return to their sport.

The rehab program for patellofemoral lesions is slightly different. Bracing is used during the first eight weeks after surgery. The knee is only allowed to bend through the first part of the joint range of motion (from zero to 20 degrees of flexion). Details of CPM use for all patients are provided by the authors.

Results of microfracture treatment are reviewed and summarized for several studies published between 1994 and 2003. Follow-up was between two and five years. It appears that weight-bearing too soon and not keeping the joint moving after surgery are major factors in cases that had a poor result.

To ensure success, patients must be chosen carefully for the microfracture technique. Follow-up during rehab is essential for the best results. Further studies are needed to identify the best rehab program for patients who are treated with microfracture.